The present invention is related to structures, such as implantable medical devices, that have an indented surface, and methods for making the same.
The present invention provides biomedical structures, and methods for their manufacture, having indentations that are selectively coated with a substance having a desirable property, such as a substance possessing a desired biological activity. For example, medical devices that are implanted into an animal body, such as the human body, often stimulate a so-called xe2x80x9cforeign body reactionxe2x80x9d which produces a fibrous capsule around the implanted device. The fibrous capsule impedes vascular communication between the body and the implanted device leading to additional, fibrous encapsulation that reduces the effectiveness and working life of the device. Thus, for example, there is a need for implantable, medical devices that have one or more surfaces adapted to promote cellular communication (such as vascularization) with the cells of the body into which the medical device is implanted.
In one aspect the present invention provides indented structures (such as biomedical structures) comprising indentations that are coated with at least one biologically active substance. The indented structures of the invention each comprise (a) a body defining a plurality of indentations, substantially all of the plurality of indentations comprising a surface layer comprising a biologically active substance; and (b) a body surface, wherein each of the plurality of indentations opens onto the body surface through a plurality of openings, and wherein the biologically active substance is not substantially present on the body surface. Examples of structures of the present invention include medical devices (such as devices that provide substrates and/or frameworks for culturing cells, tissues or organs in vitro or in vivo), including medical devices that are completely or partially implantable into a living body. The surface layer of the indentations (or at least some of the indentations) of the medical devices of the invention may comprise biologically active substances, such as proteins, that promote the growth of cells into and/or within the indentations, thereby promoting the acceptance of the implanted device by the living body, or achieve some other desired response.
In another aspect, the present invention provides methods for making indented structures (such as biomedical structures) comprising indentations that are coated with at least one biologically active substance. The methods of this aspect of the invention include the steps of (a) treating a structure, comprising a body and a body surface, to form a plurality of indentations in the body, each of the plurality of indentations (1) opening onto the body surface through a plurality of openings, and (2) further defining an indentation surface; and (b) forming a layer on at least some of the indentation surfaces, the layer comprising a biologically active substance, provided that the layer is not formed on a substantial portion of the body surface. The methods of the invention can be used, for example, to make medical devices (completely or partially implantable into a living body) comprising indentations wherein the indentations (or a portion thereof) are coated with one or more biologically active substances, such as proteins, that enhance a desired biological reaction in use, such as promotion of the growth of cells into and/or within the indentations, thereby promoting the acceptance of the device by the living body.
As more fully discussed herein, the structures and methods of the present invention can be used in any situation where there is a need to stimulate the growth of specific cell, tissue and/or organ types, or to promote some other biological function. For example, structures of the invention can be used to promote vascular communication between an implanted medical device and the surrounding tissue.